A known autostereoscopic display is described in GB 2196166 A. This known display comprises a two dimensional liquid crystal display panel having a row and column array of display pixels acting as a spatial light modulator to produce the display. An array of elongate lenticular elements extending parallel to one another overlies the display pixel array, and the display pixels are observed through these lenticular elements.
The lenticular elements are provided as a sheet of elements, each of which comprises an elongate semi-cylindrical lens element. The lenticular elements extend in the column direction of the display panel, with each lenticular element overlying a respective group of two or more adjacent columns of display pixels.
In an arrangement in which, for example, each lenticular element is associated with two columns of display pixels, the display pixels in each column provide a vertical slice of a respective two dimensional sub-image. The lenticular sheet directs these two slices and corresponding slices from the display pixel columns associated with the other lenticular elements, to the left and right eyes of a user positioned in front of the sheet, so that the user observes a single stereoscopic image. The sheet of lenticular elements thus provides a light output directing function.
In other arrangements, each lenticular element is associated with a group of four or more adjacent display pixels in the row direction. Corresponding columns of display pixels in each group are arranged appropriately to provide a vertical slice from a respective two dimensional sub-image. As a user's head is moved from left to right a series of successive, different, stereoscopic views are perceived creating, for example, a look-around impression.
One method of mounting the lenticular array to the display panel is by creating a vacuum therebetween. During the manufacture, a 2D ‘off-the-shelf’ display panel may be partly disassembled so as to prepare it for the addition of a lenticular array. FIG. 1 shows such a 2D display apparatus comprising, for example, a liquid crystal display (LCD) panel 10 and a backlight unit 12. It will be appreciated that the apparatus is shown in the normal orientation during manufacture and that when in use (viewing) the display is positioned at approximately 90° to that shown. Lateral (as shown) movement of the display panel 10 relative to the backlight is prevented by a raised support pin 14 which is part of the backlight unit 12 itself. A bezel 16 is fixed to the backlight unit by a screw 18 and serves to prevent vertical movement of the display panel 10 relative to the backlight 12. It will be appreciated that the bezel 16 typically surrounds the display panel and that FIG. 1 only shows part thereof.
When mounting the lenticular array, the bezel 16 is removed from the apparatus. The lenticular array may then be vacuum mounted to the display panel 10. As shown in FIG. 2, a modified bezel 16 is then fixed in place, again with a screw 18 for example. The bezel is modified so as to extend to clamp the edge of the lenticular plate 20.
However, several problems exist in relation to this type of mounting, particularly when the lenticular array 20 is fixed to the display panel 10 by a vacuum mount. Firstly, the lenticular plate 20 is typically much thicker and heavier than the display panel 10, particularly for large displays which may have applications in signage for example. When in use, the display panel 10 carries the entire weight of the lenticular plate 20 which puts considerable stress thereon. This increases the chance of damage to the display panel 10 or even the backlight 12.
Secondly, the tooling used to implement the mounting of the lenticular plate 20 and the panel 10 typically requires a step 22 as shown in FIG. 2, for example for a vacuum mounting method with a vacuum between the lenticular plate 20 and the display panel 10. This prevents the lenticular from extending to the edge of the display panel 10. Consequently, the flexibility of the native display panel 10 combined with the additional weight of the lenticular array may cause the panel to ‘ride’ over the support pin 14 when in use, thereby reducing the alignment accuracy or even causing complete failure of the apparatus.